DE2357716A1 - METHOD OF MANUFACTURING A STRATIFIED ROENTINE ANODE - Google Patents

Description

PHX. 6656 . Va / EVH.

9 '. 10.73.

".: PHN-6656

Anj;, cL: - _; ..: .., n .: 16. 'NOV. 1973

Process for the production of a layered X-ray rotating anode

The invention relates to a method of manufacture layered rotating anodes for X-ray tubes with a essentially made of ¥ olfram and a carrier body consisting essentially of molybdenum, and on rotary anoderi produced using this process, '',

From Dutch patent application 6916885 is discloses a method of manufacturing a laminated rotary X-ray anode with one consisting essentially of tungsten Impact area for the electrons and one essentially known from molybdenum carrier part. In this known method, a rapid deformation causing the impact process a disc-shaped in the wosentliehen

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Part made of tungsten with a disc-shaped, im substantial part consisting of molybdenum under diameter Enlargement and reduction in thickness of the two disc-shaped parts are connected. The body obtained in this way is annealed stress-free and then in the desired anode shaped.

An impact process causing a rapid deformation is to be understood here as a pre-emptying process, in which with a small number of blows, preferably with a single blow, the energy content s in one A device provided with flat press blocks a workpiece is deformed »Devices for carrying out such Processes are known per se and are axially available. Very favorable results can be achieved with a machine in which the press blocks at high speed be moved towards each other by means of gas pressure (these are the so-called pneumatic-mechanical machines).

The part of the surface hit by the electrons an X-ray rotating anode, the so-called focal point path exposed to strongly changing thermal stresses. These thermal tensions lead to a roughening of the focal point path and thus to a reduction in the X-ray dose, It is known that adding certain refractory metals to tungsten to improve the ductility of the tungsten the period of time after which roughening occurs during operation with the same load can be extended. One for Alloy metal known for this purpose is in the first place

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Rhenium; - further in the literature in this context - among others "still mentioned: Tantalum, Osmium, Iridium, Platinum, Ruteniuia, Rhodium and palladium "

In the process described above, it is natural necessary that the diameter of the both disc-shaped parts enlarged to almost the same extent will. In the patent application mentioned, it is mentioned that for this purpose the deformability of the pane parts by suitable choice of the thickness, the temperature and the type and nature of the materials that make up the disc parts "exist, can be adapted to each other.

In practice it turns out that in a number The bodies obtained are less good for processing suitable for rotating anodes. This can be the case, for example, if for a good mutual adaptation of the deformabilities , is necessary ", the thickness of the disc-shaped parts such to choose that the. layer thicknesses obtained after deformation are too small for the intended purpose. Also is it is possible that with a layer thickness of the disc-shaped parts due to the final application, materials must be used that are - less suitable or do not work optimally for the application in question,

Difficulties of this kind arise in particular, if the one disc-shaped part made of a Tfolfram-Rhenium alloy rait a rhenium content of more than 'about 2 Gew.ρ and the other part is made of a molybdenum alloy which to increase the recrystallization temperature and to

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increases the strength at higher temperatures, for example, contains small amounts of titanium and / or zirconium and possibly also contains carbon ", such as the alloys of molybdenum commercially available under the names" TZM "and" TZC "," TZM "contains according to Braun, Metall 16 (1962 ), Page 992i 0 _t 40 - 0.55 wt. ^ Titanium, 0.06 -. 0.12 wt .- ^ zircon, remainder molybdenum; "TZC" contains approx. 1.25 wt. # Titanium, 0, 15-0.25% by weight of zirconium, 0.15-0.30% by weight of carbon, the remainder being molybdenum.

The aim of the invention is to create a method for producing X-ray rotary anodes in which the described difficulty is avoided and X-ray rotary anodes are obtained with sufficient mutual adhesion of the layers with a thickness sufficient for the application in question.

According to the invention, this can be achieved with a method which is characterized in that a layered disc-shaped body made up of one layer a x "· Tungsten alloy, which can be used as an impact surface suitable for the electrons, and from a layer of a metal with one below the flow limit of the aforementioned Tungsten alloy lying yield point, which is made of tungsten or a tungsten alloy, means the latter layer with one consisting essentially of molybdenum existing schoibenförraigen body by a quick Deformation causing impact process is connected.

With the method according to the invention, an X-ray rotary anode with an impact surface for electrons can be made many Wolframlegieruiigon obtained with the

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known processes gave rise to difficulties' by reducing the deformabilities of these alloys in the forging tools used too much of those of the materials of the Trilger body were different. Moreover, it turns out that by using the layered body in general the 'adhesion to the support body made of the molybdenum alloy is greatly improved.

The layered bodies can lie on different ones, e.g. presintered or cast by forging together Discs, by spraying one of the layers onto a presintered one or cast disc, e.g. by plasma spraying and subsequent sintering of the sprayed-on layer. A layered sintered body is preferably used, which is obtained by layers of powder of the aforesaid Metals or alloys are sintered together in a form, ■

The invention will hereinafter be described by way of example the drawing explained in more detail. Show it:

1 shows a section through a sintered body two layers, , ..-"-."

2 shows a section through the structure of a disk package before deformation, ·.

3 shows a section through the structure of the disk pack after deformation, and ■

Fig. H shows a section through a finished rotating anode,

In a suitable form, a quantity of powder of tungsten or an oil drainage alloy is first put in one

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sprinkled evenly layer, after which on "this layer a lot of powder as desired for the impact area Tungsten alloy is scattered. This order can can naturally also be reversed. The whole thing is in one compressed and sintered in a non-oxidizing or reducing atmosphere until a sintered body 1 according to FIG. 1 is obtained is. Layer 2 consists of the 'desired for the impact surface Alloy, and the layer 3 made of tungsten or a tungsten alloy with a lower yield point and "a" better deformability than the first mentioned violin alloy,

The sintered body 1 is then placed with the layer 3 against a disk-shaped part h made of a molybdenum alloy. The package is heated to the desired deformation temperature and then subjected to an impact process that causes rapid deformation, ■ ·

The two disc parts 1 and h are then connected to one another by means of a blow of high energy content with the same or almost the same increase in diameter and corresponding reduction in thickness (Fig. 3). Then, for example, the body at 6 and 7 is folded over, if necessary a hole 5 is drilled to accommodate a spindle and the edge is machined off until the rotating anode shown in FIG. H is obtained;

In order to prevent oxidation during the heating of the disc-shaped parts and the subsequent deformation, it is recommended that the disc-shaped parts 1 and h in

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a thin-walled envelope made of one during heating non-melting, and with respect to the materials of the Enclose discs of inert material and heat them in this envelope and cause rapid deformation Submit striking process. Such a cover can E.g. made of 'tungsten or molybdenum sheet, which according to the Deformation can be removed. ·: ·

By means of the quick deformation The impact process will create a very good bond between the two disc-shaped parts obtained during deformation, in which the thickness of the disc-shaped parts decreases and you Increases in diameter, oxide layers are formed in the contact surface broken through and becomes fresh from one layer Material that has not been in contact with the atmosphere is intimate under very high pressure and at elevated temperature with a similar Materia.1 from the other layer in Brought in contact. - ■ ·

Sintered bodies with a density of about 85 to 95 ^ the theoretical density can be advantageous in the process can be used according to the invention «The porosity of the sintered body can be done in a known manner by compressing the material before sintering and by the nature of the sintering process be managed. The disk-shaped part from which the carrier part of the rotating anode is formed preferably consists of a material with a density of at least 90 ^ o der theoretical density. ·.

It turns out that .that thicker holds the

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Laying the sintered body is not particularly critical. If the thickness of the tungsten alloy made of impact layer is determined, the thickness of the other Layer z, B, equal to half this thickness, this thickness equal to or equal to twice this thickness. Also all thickness ratios between these values can be used. The total thickness of the sintered body can be a few millimeters be"

With the method according to the invention, among other things, X-ray anodes with an impact surface made of alloys of tungsten with one or more of the metals rhenium, tantalum, osmium, iridium, platinum, ruthenium, rhodium and palladium, an intermediate layer made of tungsten or a tungsten alloy and a carrier layer made of alloys from molybdenum with small amounts of titanium and / or zirconium and / or optionally also carbon, hafnium or boron, exemplary embodiment I.

A uniform layer of tungsten powder is applied in a cylindrical mold with a diameter of 50 mm; A layer of a powder of a tungsten-rhenium alloy with 4.5 wt., ^ rhenium is applied to this layer. Then the whole thing is compressed under a pressure of 2 _t 5 tons / cm and sintered in a reducing atmosphere at a temperature of 2200 ^{° C.}

The thus obtained wafer 1 is, 3 titanium and 0.08 Gev .- ,; i placed on a disk of the same diameter h ATIS a cast molybdenum alloy with 0.5 GeV / / zirconium;

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the package is heated to a temperature of ca, 160o C ^0. The whole thing is shaped into a disc with a diameter of 120 mm with a single stroke in a pneumatic-mechanical machine. The thickness of the package is then approx. 8 mm. The whole is stress-free annealed at a temperature of 1000 ⁰ C and finally presented processed by conventional methods to a rotating anode. The tungsten-rhenium layer 2 now has a thickness of 0.8 mm, while the ¥ olframschicht 3 has a thickness of 1.2 mm and the carrier 4 has a thickness of 4 mm.

In a corresponding manner, sintered bodies were used in the manufacture of a rotating anode, in which the upper layer of tungsten-rhenium with 4.5 wt. <%> Rhenium and the other layer of tungsten-rhenium with 0.5 wt . ^ o rhenium, 1.5 wt. ^ rhenium or 2 wt.fo rhenium consisted, in all cases a uniform deformation and good adhesion between the sintered body and the carrier body were obtained during the deformation process. Embodiment II

A rotating anode was produced in a corresponding manner, with a sintered body made of a layer of a tungsten-niobium alloy with 2 wt I. mentioned molybdenum * alloy was connected. The Wolfrani layer and the tungsten-niobium layer both had a thickness of approx. 1 mm.

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Embodiment 111

In a corresponding manner, a rotary anode was prepared 'in which a sintered body of a layer of a tungsten-rhenium-tantalum alloy containing 3 wt / o rhenium, 0, h tantalum, balance tungsten, and a layer of tungsten by means of the side of the liolframschicht was connected to a disk made of the molybdenum alloy mentioned in Example I.

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Claims (1)

"! V -." ". _..- '. PHN.6656. 9/10/73. ' PATENT CLAIMS: 1.y ■ method for Hersteilung a layered X-ray rotary anode having a substantially made of tungsten "sawn _s stationary impact surface for the electrons and a group consisting of molybdenum in ■ substantially support body, wherein by means of a quick deformation-giving impact operation a disc-shaped substantially of tungsten existing Part with a disk-shaped part consisting essentially of molybdenum with a diameter increase and reduction in thickness of the two disk-shaped parts and the body thus obtained is brought into the desired anode shape, characterized in that a layered disk-shaped body made of a layer of a tungsten alloy is used as Impact layer for the electrons and a layer made of a metal with a flow limit lying below the flow limit of the aforementioned tungsten alloy. Made of tungsten or a tungsten alloy by means of the latter layer with the essentially A disk-shaped part consisting of molybdenum is connected by the impact process causing a rapid deformation, 2, method according to claim 1, characterized in that a layered disk-shaped sintered body is used, which is obtained by layers of powders of the metals to be used in a mold be sintered together, 40982A / 0722 - 12 - 'PHN ". 6656» 9/10/73. 3 »Method according to claim 1, characterized in that that a layered, disc-shaped sintered body made of a layer of a Volfram rhenium alloy is used as an impact layer for the electrons and a layer Tungsten or a tungsten-rhenium alloy with a lower rhenium content than the first-mentioned tungsten-rhenium alloy and a disc-shaped part made of a Molybdenum alloy with 0.4-0.55 Ge ^ titanium and 0.06-0.12 wt. Zircon can be used, k. Layered X-ray rotating anode obtained by the method according to claims 1 to 3. 409824/0722. ORIGINAL INSPECTED